Inconsistent fsl_get_sys_freq() implementation

Inconsistent fsl_get_sys_freq() implementation

[Wolfgang Grandegger]

Hello,

we realized an inconsistent implementation of fsl_get_sys_freq():

http://lxr.linux.no/linux+v2.6.29/arch/powerpc/sysdev/fsl_soc.c#L80

For 826x and 827x boards, the function is available but it cannot be
used because the "bus-frequency" property is not defined for the SOC and
U-Boot also does not try to do a fixup. I think that's a mistake, and
the DTS files and U-Boot should be fixed, right?
Furthermore, I find the name confusing. fsl_get_soc_bus_freq() would be
more appropriate also to distinguish from the frequencies of the CPU.
And why does the MPC52xx use a different name mpc52xx_find_ipb_freq()
for that frequency? It makes support for common hardware like I2C awkward.

Thanks.

Wolfgang.

Re: Inconsistent fsl_get_sys_freq() implementation

[Grant Likely]

On Tue, Mar 31, 2009 at 1:28 AM, Wolfgang Grandegger <wg@grandegger.com> wrote:
>
> Hello,
>
> we realized an inconsistent implementation of fsl_get_sys_freq():
>
> http://lxr.linux.no/linux+v2.6.29/arch/powerpc/sysdev/fsl_soc.c#L80
>
> For 826x and 827x boards, the function is available but it cannot be
> used because the "bus-frequency" property is not defined for the SOC and
> U-Boot also does not try to do a fixup. I think that's a mistake, and
> the DTS files and U-Boot should be fixed, right?
> Furthermore, I find the name confusing. fsl_get_soc_bus_freq() would be
> more appropriate also to distinguish from the frequencies of the CPU.
> And why does the MPC52xx use a different name mpc52xx_find_ipb_freq()
> for that frequency? It makes support for common hardware like I2C awkward.

I haven't looked at fsl_get_soc_bus_freq(), but if the functions are
duplicated, then I've got no problem changing the 52xx support to use
common code.

g.

--
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.

Re: Inconsistent fsl_get_sys_freq() implementation

[Wolfgang Grandegger]

Grant Likely wrote:
> On Tue, Mar 31, 2009 at 1:28 AM, Wolfgang Grandegger <wg@grandegger.com> wrote:
>> Hello,
>>
>> we realized an inconsistent implementation of fsl_get_sys_freq():
>>
>> http://lxr.linux.no/linux+v2.6.29/arch/powerpc/sysdev/fsl_soc.c#L80
>>
>> For 826x and 827x boards, the function is available but it cannot be
>> used because the "bus-frequency" property is not defined for the SOC and
>> U-Boot also does not try to do a fixup. I think that's a mistake, and
>> the DTS files and U-Boot should be fixed, right?
>> Furthermore, I find the name confusing. fsl_get_soc_bus_freq() would be
>> more appropriate also to distinguish from the frequencies of the CPU.
>> And why does the MPC52xx use a different name mpc52xx_find_ipb_freq()
>> for that frequency? It makes support for common hardware like I2C awkward.
> 
> I haven't looked at fsl_get_soc_bus_freq(), but if the functions are
> duplicated, then I've got no problem changing the 52xx support to use
> common code.

The name used for devices using CONFIG_FSL_SOC is fsl_get_sys_freq(),
see the link above. Both functions return the bus frequency of the SOC
but they are implemented differently and allow some variation (which
needs some double-checking).

Wolfgang.